A new approach to complete horizontal wells is proposed to make futurestimulation work much more effective. Current well design formulations, largelyinfluenced by vertical well technologies, do not tend themselves well tofurther stimulation. Treatment of wells that have been depleted tononeconomical levels may generate marginal production increases.
The new method uses hydrajetting technology to enhance the ability tosuccessfully stimulate a horizontal well. It uses a hydrajetting tool that iscapable of creating fan-shaped slots in the formation behind the casing inorder to direct fracture initiation correctly. Only limited size slots are cutthrough the casing, thus maintaining its integrity. Using this new approachwill result in more effective treatment of localized areas, and willdrastically improve stimulation or damage-bypass treatments. Tortuosities offracture paths are reduced if not eliminated. Patent applications have beenfiled on the subject matter contained in this paper.
Horizontal wells have a large potential to improve the oil production ratesand ultimate recovery of many reservoirs. This improves the attraction of theindustry to this technology, especially with the advanced stages of drillingand completion technology in this area. In fact, it has been demonstrated thatre-entering an existing vertical wellbore to drill a horizontal segment iseconomically feasible.
When low cost is the overriding concern in completing a horizontal well, openhole completions are generally selected if borehole stability is not aproblem. Such completions, however, do not provide options for remedial actionsin the future. In addition, this type of completion does not allow effectivemeans for abandoning the well, and may be costly to manage during the laterstages of the life of the well.
Slotted liner completions provide advantages over the openhole method bytheir relatively low cost, yet better protection against wellbore collapse.However, as in openhole completions, slotted liners provide very few optionsfor remedial procedures.
Cemented casing completions are the most expensive, but they provided, mostoptions currently available in vertical well technology. Effectivestimulations, isolation of zones, and other remedial actions are possible. Wellabandonment can also be performed effectively.